NAT typing address error

Description

VB has a weird behavior when I’m setting the NAT rules:
If I set an IP like 10.0.0.1, sometimes (not always - the first line is not affected) when I press OK there is an error like “no value of the ports of host & guest can be set to 0”.
If I press OK in this new window, then I select the host’s IP and then I
write the value as a string of 3 digit, the value seems to be accepted.

I think that this is definitely a bug, I don't know if the NAT works with this workaround.

The screenshots and the logs follow as attachment.
pls reply to dieghe66@…